A magnetoresistive effect element described in Patent Literature 1 has a first half-metal ferromagnetic layer, a second half-metal ferromagnetic layer, and a nonmagnetic metallic substance layer a nonmagnetic spacer layer) sandwiched between the first half-metal ferromagnetic layer and the second half-metal ferromagnetic layer. These three layers constitute a magnetoresistive layer. At least one of the first half-metal ferromagnetic layer and the second half-metal ferromagnetic layer is formed of a Heusler alloy, and the nonmagnetic metallic substance layer is formed of Ag.